Expansion Valve Control; Special Operation; Snow Falling Protection Fan Mode; Oil Recovery Operation - Fujitsu Airstage V series Service Manual

4-3-3 Snow falling protection fan mode

When turning on DipSW2-2(Snow falling protection fan mode) and the outdoor unit is stopping
and Tout is below 5
When the outdoor unit starts the operation or Tout is above 7
fan control exits Snow falling protection fan mode.
Snow falling protection fan mode : Outdoor unit fan operates on

4-4 EXPANSION VALVE CONTROL

Initialization conditions
EEV 1 Turn on outdoor unit power
24 hours have passed since
the last initialization,and the
outdoor unit has stopped.
EEV 2 Turn on outdoor unit power
< Cooling mode >
500 pulses basically.
< Heating mode >
EEV is controlled so that the system reaches closer to the target discharge temperature that is calculated from
high and low pressure.

4-5 SPECIAL OPERATION

4-5-1 Oil recovery operation

(1) Purpose of the operation
The amount of refrigerant lubricant oil which has been transported to the indoor units
and the connection pipe with the refrigerant will become large as the operation time of compressor increases.
It is necessary to recover the oil back into the outdoor unit for a certain time interval
in order to prevent compressors from damaging due to lack of lubrication oil.
(2) Starting conditions
Starting conditions of oil recovery operation are as follows.
1
Oil recovery from the gas main pipe (Only cooling mode)
If the overheating condition is continued over 30 minutes, where the difference between compressor suction
sensor temperature and low pressure sensor temperature (Suction SH) is higher than 10degC (Normal control
if Suction SH becomes small afterward),
2
Accumulated time of oil recovery operation
(3) Operation
1
Indoor EEV is gradually opened. (Oil is recovered together with refrigerant.)
2
Operating compressor
EEV Opening (Indoor/Outdoor unit): Controlled pulse (as normal operation mode).
FAN speed (Indoor/Outdoor unit)
Oil recovery operation time
(4) Others
During the oil recovery operation,
and appears on the simple remote controller.
The operation indicators (LED) of the indoor units flash slowly.
, fan control enters Snow falling protection fan mode.
"Hi" mode for 1 minute in every 30 minutes.
operation
0 - 500 pulses
0 - 500 pulses
: 2 compressors of each slave type outdoor unit
DC inverter compressor of master type outdoor unit (at 70Hz) and 1 constant
speed compressor.
: Controlled fan speed (as normal operation mode).
: When suction sensor temperarure(Thermistor11) of master unit
detects fall in the certain temperature, oil recovery operation is terminated.
Oil recovery operation time is a maximum of 6 minutes.
appears on the display of wired and central remote controller,
,
Control range
stop refrigerant
discharge
0 pulses 400 pulses
0 pulses Controlled
3(Cooling) / 8(Heating) hours
04-06
refrigerant
storage
500 pulses
0 pulses